Portable derrick



July 12, 1949.- D. R. MOORE 2,476,210

PORTABLE DERRICK Filed Sept. 17', 1921s 3 Sheets-Sheet 1 I Snoentor Dewey R. Moore July 12, 1949., D. R. MOORE 2,476,210

PORTABLE DERRICK Filed Sept. 17, 1946 3 Sheets-Sheet 3 Bummer Rm dttorucu Fatented juiy i2, 1949 UNITED STATES PATENT OFFICE 2,476,210 I PORTABLE DERRICK Dewey R. Moore, Dallas, Tex. Application September 17, 1946', Serial No. 697,553

1 Claim.

may be used in connection with well drilling or servicing operations, although not limited thereto.

In the past there have been proposed numerous types of portable derricks such as might be used for the aforementioned purposes, but so far as I am aware, all of them are deficient in one way or another. Such a structure (i. e. portable derrick) should not only be of rugged construction, but it must also be so constructed as to enable its easy and speedy dismantling, transportation and re-erectlon. In addition, it should be easy and inexpensive to manufacture and maintain; otherwise it will not be economically feasible.

It is among the objects of the present invention to provide a portable derrick which attains all of the foregoing objectives.

Another object is the provision of an apparatus of the class described which requires a minimum of power to operate into its erect and dismantled positions.

The invention, then, comprises the features hereinafter described and as particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative of several of the number of ways in which the principles of the invention may be employed.

In said drawings:

Figure 1 is a side elevation of the apparatus of the invention, showing in solid lines the mast in its prone position, the dotted lines illustrating the same in erect position;

Figure 2 is a plan of the mast in its erect position;

Figure 3 is a side elevation illustrating the relative positions of the elements of the apparatus during the course of the erecting operation; and

Figure 4 is a schematic perspective.

In order that the teachings of the present invention will be most readily understood, the apparatus will first be described in its prone and transportable position.

Referring more particularly to the drawings, the numeral I generally designates a mast comprising four leg members 2, the same being arranged in pyramidal fashion and joined together at the base and at other desirable points by suitable transverse bracing members 3. verging ends of the leg members 2, at the top of the pyramid formed thereby, are suitably Joined together; and between them there is mounted a crown block 5.

One side of the mast I is pivotally connected as at l to a supporting base 8. This permits the mast I to lie on its side, as shown in Figure 1, whereupon both the base 8 and the mast may be easily transported as a unit.

The supporting base 8 also carries a drum III which may be rotated manually or through a suitable prime mover (not shown). The usual drilling line II is anchored to the base 8 at a point 9 which intersects the axis of the pivotal connection 7 between the mast and the base, and the said drilling line is strung in the usual manner over the crown block 5 and the usual traveling block I2 to the hoist drum III, the line being in six or eight courses or lines over said blocks.

According to the teaching of the present inven- The C011- tion there is supported on the upper side of the recliningmast, at a position proximate but spaced from its lower end, a vertically extending boom I5 which is made up of suitable longitudinal structural members I6 and transverse and diagonal structural members I8 and I9, respectively. Atopthe boom I5 there is mounted a pair of pulleys 20 which rotate "on an axis whicnis parallel to the axis of pivotal movement of the mast I on the base 8. A similar pair of pulleys 2| is mounted on the underside of the mast I immediately below the boom I5; and a similar pair of pulleys 22 is mounted on the base 8 at a position which is beyond thedrum I 0 and the path of movement of the mast I toward it as the erection proceeds.

The traveling block I2 carries the usual hook 24, over which there is looped a line 26 which is divided into two ropes. These two ropes of the line 26 extend over the-pulleys "2| on the underside of the reclining derrick, over the pulleys 20 atop the boom I5, around the pulleys 22 which are ailixed to the base 8, and thence to anchorage 21 atop the boom I5 and adjacent the pulleys 20. Guy wires 28 and 30 may be employed to adequately support the mast I during erection.

With the foregoing arrangement of the holsting line ll and the separate line ll, it will be seen that the rotation of the drum ll will shorten the eflective length of the said hoisting line. This results in movement of the traveling block it in an outward direction toward the crown block 5, tensioning the "dead or constant length lines 2. The pulley forces thus applied to the lines II and 28 result in rocking the derrick about its pivotal connection I with the base unit 8 and the consequent raising of the derrick from a horizontal to a vertical position. As the traveling block i2 moves outwardly, the loop or loops formed by the "dead" lines 28 shortens, and since the forces thereby established are directed downwardly and angularly from the pulleys 20, swinging movement 01 the derrick takes place. It is, of course, preferable to use the lines II and 26 in multiple orderso that safer loads may be carried.

Due to the hereinbetore described arrangement of pulleys, a great mechanical advantage is obtained. That is, in raising the derrick, the trav cling block I! will move a great distance, but the stress in each or the lines will be inversely reduced. A further advantage of the foregoing method and arrangement of elements resides in the tact that there are no lines extending across the derrick floor during the erection of the derrick, thereby eliminating a hazard to the operators.

In lieu of the base 8, the elements of the mast I may be assembled on the ground and pivoted thereon. Likewise, the drum l0 and the pulleys 22 may be separately mounted on suitable supporting media to thereby dispense with a supporting base.

While I have shown and described certain specific embodiments of the present invention, it will be readily understood by those skilled in the art that I do not wish to be limited exactly thereto, since various modifications may be made 4 without departing from the scope of the invention as defined in the appended claim.

I claim:

A derrick structure comprising a base, a derrick tower hinged at its lower extremity to an edge of said base and adapted to occupy either a prone position extending outwardly from said base or an upright position above said base, a boom fixed to the .lower portion of said tower and extending perpendicularly therefrom, a traveling block and a crown block in said tower, a winch mounted on said base, a variable length cable secured to said winch and passing around said crown block and said traveling block and dead-ended on said base, a pair of laterally spaced coaxial pulleys mounted on the lower portion of said tower within the confines thereof on the side opposite juncture with said boom, a' pair of laterally spaced coaxial pulleys mounted on said base spaced from the edge to which said tower is hinged, a pair of laterally spaced coaxial pulleys mounted at the extremity of said boom, and a dual fixed length cable connected at its ends to the extremity of said boom, thence passing under the pulleys on said base, over the pulleys on said boom, and under the pulleys on said tower and having a bight at its mid portion connected to said traveling block, said base being clear of highly tensioned cables.

DEWEY R. MOORE.

REFERENCES CITED The following references are of record in the file or this patent:

UNITED STATES PATENTS Number Name Date 2,267,705 Athy Dec. 30, 1941 2,271,578 Woolslayer Feb. 3, 1942 2,363,106 woolslayer Nov. 21, 1944 2.403.081 Hilborn July 2, 1946 

